Question

7 9 si 14 va tog fau 50 de puncte și coroniță​

Answer 1

Explicație pas cu pas:

7.

$f(1) + 9f\Big( \dfrac{1}{9} \Big) - 10f\Big( \dfrac{1}{25} \Big) = \sqrt{1} + 9 \sqrt{\dfrac{1}{9}} - 10 \sqrt{\dfrac{1}{25}} = 1 + 9 \cdot \dfrac{1}{3} - 10 \cdot \dfrac{1}{5} = 1 + 3 - 2 = 4 - 2 = 2$

9.

$\sqrt{x - 2} = 3 \iff x - 2 = 9 \\ x = 9 + 2 \implies x = 11$

14.a)

$= \sqrt[3]{1} + \sqrt[3]{27} - \sqrt[3]{8} + \sqrt[3]{ \dfrac{1}{8} } \cdot \sqrt[3]{64} =$

$= 1 + \sqrt[3]{ {3}^{3} } - \sqrt[3]{ {2}^{3} } + \sqrt[3]{ \dfrac{1}{ {2}^{3} } } \cdot \sqrt[3]{ {4}^{3} } \\ = 1 + 3 - 2 + \dfrac{1}{2} \cdot 4 = 2 + 2 = 4$

b)

$\sqrt[3]{4x - 1} = 3$

$4x - 1 = 27 \iff 4x = 28 \\ \implies x = 7$